Periodic switch assembly with improved rotor contact structure

ABSTRACT

In a pulse generating switch assembly the rotatable slip ring is comprised of a conductive sleeve having a continuously conductive groove formed directly therein. At least one insulating ring and one conductive ring are mounted directly on the sleeve with axially directed projections on the insulating ring intermeshing between radially projecting segments on the conductive ring. Thus, a portion of the circumference of the combined ring presents alternating conductive and insulating segments and a groove is formed therein. Wire brush means are mounted in resilient contact with the grooves so that upon rotation of the slipring assembly a series of pulses will be generated.

United States Patent [72] Inventor Kunio Endou Tokyo, Japan [21 Appl. No. 36,538 [22] Filed May 12, 1970 [45] Patented Jan. 4, 1972 [73] Assignee Mitsumi Seiko Kabushiki Kaisha Tokyo, Japan [32] Priority May 16, 1969 [3 3] Japan [31 44/37595 [54] PERIODIC SWITCH ASSEMBLY WITI-IIMPROVED ROTOR CONTACT STRUCTURE 6 Claims, 31 Drawing Figs.

[52] US. Cl 200/24, 200/8 A, 200/25 [51] Int. Cl I-I0lh 19/56, I-I01h 21/76 [50] Field of Search 200/24, 25,

Primary Examiner-J. R. Scott Attorney-Sughrue, Rothwell, Mion, Zinn & Macpeak ABSTRACT: In a pulse generating switch assembly the rotatable slip ring is comprised of a conductive sleeve having a continuously conductive groove formed directly therein. At least one insulating ring and one conductive ring are mounted directly on the sleeve with axially directed projections on the insulating ring inter-meshing between radially projecting segments on the conductive ring. Thus, a portion of the circumference of the combined ring presents alternating conductive and insulating segments and a groove is formed therein. Wire brush means are mounted in resilient contact with the grooves so that upon rotation of the slipring assembly a series of pulses will be generated.

PATENTED JAN 41972 3.632 911 sum 1 [1F 3 FIG-l FIG'Z 1s I? 25 I6 PRIOR ART PATENTEB M 4m 3532' 91 1 SHEET 3 [IF 3 FIG.28 I04 PERIODIC SWITCH ASSEMBLY WITH IMPROVED ROTOR CONTACT STRUCTURE This invention relates to a pulse signal generating switch assembly of the multicontacts and multicircuits type and comprising a stationary contact assembly and a movable contact assembly arranged to cooperate with each other.

The improvements of the invention comprise in combination of a plurality of contact wires arranged in parallel to each other, a plastic base firmly positioning therein the root portions of said contact wires, said wires and said base constituting said stationary assembly, a metallic sleeve, a plurality of contacting ring grooves adapted for resilient and pressure contact with said wire contacts, respectively, each of a selected 7 number of said contact grooves comprising each a series of conducting and nonconducting elements arranged alternately and in a continuous ring way, at least one of said grooves being formed on said sleeve, with a rotor ring means mounted on said sleeve and formed with said grooves other than these formed on said sleeve.

This invention relates to a pulse signal generating switch assembly of the multicontacts and multicircuits type.

A main object is to provide a switch assembly of the above kind, capable of generating alternatively two series of pulses of accurate nature and relying exclusively upon the mechanical and electrical contacting and interrupting action. I

A further object of the invention is to provide a rotary switch assembly which is highly effective for use as a pulse generating mechanism adapted for the operation control of an autoreturn autochanger mechanism of the Stahl-type tape recorder.

These and further objects, features and advantages of the invention will become more apparent when read the following detailed description of the invention by reference to the accompanying drawings in which a comparative conventional switch assembly and substantially preferred embodiment of the invention.

In the drawings:

FIG. I is a schematic side view of a conventional comparative switching mechanism.

FIG. 2 is a schematic and highly simplified explanatory and operational view of the switching mechanism shown in FIG. 1.

FIG. 3 is a side view of a three-contact type stationary contact assembly employed, as an example, in the invention switching assembly.

FIG. 4 is a plan view of the stationary contact assembly shown in FIG. 3.

FIG. 5 is a substantially sectioned side view of a movable contact assembly employed, as an example, in the invention and adapted for cooperation with the stationary contact assembly shown in FIGS. 3 and 4.

FIG. 6 is a schematic plan view, partially sectioned, of the essential switch unit comprising the' above-mentioned stationary and movable contact assemblies positioned in their cooperating condition.

FIG. 7 is a side view of the switch assembly shown in FIG. 6.

FIG. 8 is a plan view of a member of two-piece base, as a preferred embodiment for support of stationary wire contacts.

FIG. 9 is a half-sectional view of the base element shown in FIG. 8, the section being taken along a section line A-B shown therein.

FIG. 10 is a sectional view taken along a section line C -D shown in FIG. 8.

FIG. 1 l is a substantially half-sectional side view of a metallic sleeve as a mounting and contacting member of the movable contact assembly.

FIG. 12 is a partially sectional frontview of an insulator ring.

FIG. 13 is a partially sectional view of the insulator ring shown in FIGS. 5 and 12.

FIG. 14 is an elevational view of an rotary member of the movable contact member.

FIGS. 15 and 16 are end views of the rotary member shown in FIG. 14.

FIGS. 17 and 18 are front view and a plan view of a reng contact as a member of the movable contact assembly. FIGS. 19 and 20 are a partially sectional elevation and a front view of stepped metal ring, as a member of the movable contact assembly.

FIG. 21 is a developed plan view of the arrangement of .three rows of contacts formed on the movable contact assembly.

FIG. 22 is an explanatory and highly simplified drawing for the explanation of the working mode of the switch assembly having movable contact arrangement shown in FIG. 21.

FIGS. 23 and 24 are an end view and a half-sectional elevational view of a two-contact type switch assembly, as a modification from the foregoing.

FIGS. 25, 26 and 27 are explanatory views for the explanation of the twoand three-wire contacts type switch assemblies.

FIG. 28 is a sectional view of essential parts of a cassette tape recorder fitted with the novel switch assembly.

FIG. 29 is an exploded and partially broken away perspective view of a reel shaft of said tape recorder, said shaft being fitted thereon with the movable contact assembly.

FIG. 30 is a perspective view of a stationary wire contact adapted for cooperation with said movable contact assembly shown in FIG. '29.

FIG. 31 is a wiring diagram for control of the tape reeling operation of the tape recorder shown in FIG. 28 and comprises the novel switch according to this invention.

In advance of disclosing detailed description of a preferred embodiment of the present invention, a comparative conventional switching unit will described hereinbelow by reference to FIGS. 1 and 2.

In these figures, the numeral 10 denotes a rotary cam having a square cross section. A rigid stationary mounting member 11 is provided and mounts rigidly in turn the root portions of three-wire spring contact 12-14 which are arranged, as shown, substantially in parallel to each other. The central wire contact 13 is longest in its length and kept always in resilient contact with the rotary cam 10. These members 10-14 are so designed and arranged that when the central contact 13 is kept in contact with any one of the four sides of the square cam 10, the contact 13 is also in contact with the upper stationary contact 12. Since these contacts 12-14 are connected to certain elements of a control circuit, for instance, adapted for control of the tape reeling operation of a tape recorder, as will be more fully described hereinafter.

When the rotary cam 10 is rotated in a constant speed as conventionally, the central stationary contact 13 performs an oscillatory movement between its full-line and dotted line positions and alternately makes with the upper and lower stationary contacts 12 and 14. This alternate on-off switching operation will be clearly seen from the schematic representation shown in FIG. 2.

A considerable drawback as met with the above-mentioned conventional switching mechanism is such that a remarkable reaction force is fed back to the rotary cam 10, the torque applied thereof becoming fluctuant, thus resulting in an uneven rotational speed of the square cam. In addition, the distance between the contacts is defined by the highly wearable square cam, and the preciseness of the pulse shape is considerably injured. It has been therefore experienced, even when the thus generated output pulses should be shaped in a differentiating circuit, the attainable improvement of the pulse form would only be minor. The generation of precise pulses had to be relied upon the pure electronic circuit.

As will be more fully disclosed hereinafter, the main feature of the present invention resides in the provision of a stationary contact means and a movable or rotary contact means. The first means comprises a plurality of elastic contact wires arranged in parallel to each other; each of said wires if formed with a positioning means which may preferably comprise a folded up channel formed in its base end and positioned rigidly by molding in the material of a base member made preferably of a plastic or by being firmly squeezed by a pair of base elements which are detachably, yet firmly coupled together by pressure fit. The second means is comprised of a metallic mounting sleeve, having a plurality of contacting ring grooves; one of said grooves being formed on the periphery of said sleeve and each of the remaining grooves comprising a circular arrangement of separated contact elements. The thus formed rotor is rotatably mounted with said sleeve. The switch shaft, as will be more fully described, is rotated through a reduction gearing from an electric motor and normal driven at a relatively slow speed and the duration of period of the pulse may generally be long. Therefore, the representative application as an electronic controller for the tape reeling mechanism of a tape recorder, as an example, will be highly benefited over the aforementioned prior technique.

Next, referring to FIGS. 3-4, a preferred embodiment of said first means or more specifically the stationary contact assembly will be described in a more specific way.

The numeral 15 denotes a mounting member of base shaped into a hexahedron and mode of a superior insulating resin, such as Duracon." Three contact wires 16; 17 and 18 formed with positioning means such as at 16a; 17a and 18a, shaped preferably into a channel-shaped configuration as shown, are molded in the material of the base 15 in the present embodiment. The contact wire has preferably a diameter of 0.45 mm.; having naturally enough elasticity and a length in the order of 35 mm.

As will be more fully described hereinafter, the embodiment shown in FIGS. 8-10, the base 15 is divided into two separate elements 15A and 158, each having positioning pins 15a 15b and their mating holes 15c; 15d adapted for push-in engagement with or pullout disengagement from each other. For assisting the tight combination of base elements 15A and 15B, proper glueing agent may naturally be used.

For fixed attachment of the base 15 to a proper stationary member, such as chassis panel, of an electric or electronic equipment, it is bored with openings 19 and 20 (FIG. 3) through which fixing screws or the like means are inserted.

On of the base elements such as at 15A is formed with a sole elongated lateral opening 21 which serves for insertion of fixing screw means or the like for fixed attachment of the base assembly 15A; 15B to a certain stationary member as before.

In FIG. 5, a movable contact assembly is shown which comprises a metallic sleeve 22, preferably made of phosphorous bronze. A detail view of this sleeve is shown in FIG. 11. This sleeve 22 comprises a cylindrical main part 22a and a flange part 22b, the latter being formed with a ring groove 23 and a ring shoulder 24 adapted for mounting a ring-shaped insulating seat 25 which is shown in FIGS. 12 and 13. When assemblying, the outer end 220 of cylindrical part 22a is caulked or hammered.

The base element 15A or 158 is formed with three axially parallel and recessed grooves 40a, 40b, and 40c for receiving the positioning projections. When the base elements 15A and 15B are conjointed together under pressure, the contact wires 16-18 are automatically positioned.

When assembling the movable contact unit, the insulator ring seat 25 is slid onto the ring shoulder 24. Next, two contact ring 27a and 27b (FIG. made preferably of phosphorous bronze, are attached to a rotor ring 26 made preferably of plastic from both side thereof. This contact ring is shown generally at 27 in FIGS. 17-18. The thus-assembled unit is slid onto the cylindrical part 22a.

Further, one more ring seat 25 shown in FIGS. 12-13 is taken out and conjointed together with a stepped metal ring 28 shown in FIG. 19 and then, the thus assembled unit is sled on the cylindrical part 22a and finally the outer end 22c of the cylindrical part is caulked for the realization of a whole assembly.

The thus-fabricated and assembled stationary and movable contact assemblies are shown in FIGS. 6 and 7 in their state of mutual cooperation. It will be seen that the contact wires 16, 17 and 18 of stationary contact assembly stationary is positioned stationarily as was referred to hereinbefore, and the rotatable contact assembly is positioned in close proximity thereof, so as to bring them into mutual cooperation with each other. The contact wires 16, 17 and 18 are brought into and kept in resilient pressure contact with contact grooves A, B and C respectively.

FIG. 21 shown schematically the contact grooves A, B and C in their contact arrangement. The first contact groove A is formed on the metallic ring 22, thus providing a kind of continuous conductive way acting at the same time as a bearing means. This constitutes a common contact A. The ring 22 is connected with a proper input, for instance, a current source, although not shown.

The contacts arrangement on the groove B and C is shown schematically at B and C in FIG. 21, respectively. The arrangement is such that the conductive elements a and the interrupting elements b are arranged in an alternating way. As seen from FIGS. 17 and 18, several equidistantly and circumferentially arranged contacting elements are provided in the form of respective radial projections 27a.

The insulating or interrupting elements b are constituted by a circularly and equidistantly and axially projecting small projections 26a formed on each side surface of a rotor member 26 made of an insulating material, said projections being most apparent especially from FIGS. 15 and 16.

The mutual distance between each two successive projections b is so selected as to coincide with the peripheral length of each of the small projections 27a.

The radial length common to all the projections 26a; 27a as measured from the outer periphery of each of these projections to the axis of the rotor assembly 16 is selected to a certain predetermined value.

When two contact rings 27 are assembled to rotor member 26 at its both surfaces so as to provide the ring-shaped contacting ways B and C, respectively, each of these ways representing a number of alternatingly combined conducting and interrupting contact elements a and b positioned in a common circle having a predetermined radius. This circle representing a continuous contacting way, as above-mentioned and when seen in its entirely, is a practically a smooth contacting ring surface in the form of a switching ring groove.

The cooperating condition between the thus-shaped assembled and properly positioned is shown specifically in FIGS. 6 and 7. As seen, contact wire 16 is kept in elastic contact with contacting ring groove A; contact wire 17 with B; and contact wire 18 with C, respectively. The movable contact parts are driven at a predetermined constant speed from an electric motor, not shown, as i conventionally employed for the rotary switch. I

As seen from FIG. 21, each of the conducting contact elements a in the groove B corresponds to one of the nonconducting contact elements b when seen laterally of the movable contact assembly.

When contact wire 17 is brought into a conducting element a, wire 18 is thus brought into contact with a neighboring nonconducting element b in the neighboring groove C.

Current is therefore conveyed from the current source through contact wire 16, the now contacted conducting element a in the groove B, contact wire 17 to a certain control circuit. This switched condition is shown schematically in FIG. 22.

In this case, wire 18 is positioned in its interrupting state.

On the contrary, when wire l8'is brought into contact with one of conducting elements a in the groove C, wire 17 contacts one of the nonconducting elements b in the groove B. Current is thus conveyed through wire 6, the now contacted conducting element a in the groove C and wire 18 to a certain operation control circuit to be described. This alternate switched position is shown by a dotted line in FIG. 22. Under this condition, contact wire 17 is in its interrupting one.

It will be clearly seen that when two circuits are controlled by the switch assembly so far shown and described, and when one of these circuits is brought into conductive, the other circult is brought into its interrupted state, and vice versa. In this way, a two-contact switching device is provided, capable of substantially obviating otherwise possible abrupt "dancing" movement of contacting members.

In the arrangement shown in FIGS. 6 and 7, all the three contact wires 16-18 are arranged to contact the respective grooves A, B and C from one side of the movable contact assembly.

In modified arrangement shown in FIG. 26, one contact wire 18 contacts the groove C from the opposite side wherein the remaining two wires 16 and 17 are positioned. In this way, the contacting pressure exerted by the three contacts are balanced out in a substantial way. Other alternative contacting modes, so far as the contact wires are concerned, are naturally conceivable.

In FIGS. 23, 24, 25 and 27, a simplified two-contact wire type switch, yet embodying the novel teachings of the invention, is shown. Similar constituents are represented by the corresponding same reference numerals and symbols as before, each being attached with a prime, thus no further analysis of the constructional and functional features of the present modified embodiment will be omitted without prejudice.

It should be mentioned, however, that although the contact ring 27' has a generally similar basic configuration as before, the space formed between each successive two radial projections 27a is filled out by a nonconducting resin element 30 fixedly mounted in position by moulding.

When this modified switch assembly is used as in the position shown in FIG. 27 a series of on-off pulses can be sent out. The wiring connection with the current source and the circuit to be controlled, not shown, may easily be supposed from the foregoing description of the main embodiment.

In a still modified arrangement, the two contacts are arranged to contact with the respective movable contact grooves from the opposite sides thereof, in a similar way as shown in FIG. 26.

A representative mode of the practical application of the inventive switch assembly will be described by reference to FIGS. 28-31.

FIG. 28 represents standardly conventional cassette; and 102 tape delivery reel shaft on which the movable contact assembly shown in FIG. 5 is fixedly mounted while the stationary three-contact wire type assembly shown in FIGS. 4 and 30 is fixedly mounted on the housing 103 of the tape recorder.

When the tape recorder is operated for a longer time period than a certain specified time, and the tape shown at 104 is brought to its end, the wire switch detects such position and an electromagnetic plunger is brought thereby into actuation so as to pop up the cassette and at the same time to interrupt the current.

When cassette tape is delivered from the tape delivery reel attached to shaft 102 under the regular condition, motion is transmitted from he shaft to the movable contact assembly. When it is assumed that two wire contacts 16 and 17 are brought into conductive state, condenser C, shown in FIG. 31 is charged through resistor R,. Next, when wire contacts 17 and 18 are brought into conducting state, charge will be discharged from condenser C, through resistor R,. In this way, the switching operation for charge and discharge of the condenser C, is efiected by the switch assembly so far shown and described.

By the charge and discharge operation of the condenser C,, practically continuous current I(about 0.2-1.0 ma.) flows and the collector-emitter voltage V, at the transistor TRl is kept at practically nil and therefore transistor TR2 is kept in its nonconducting state. Thus, transistors TRl and TR2 are nonoperative.

Under these conditions, no current will flow through plunger coil 105, and a control switch 106 arranged to be controlled by the plunger, only shown by two parallel vertical lines along the axis of the coil 105, is kept in its closed posit l lilhen the delivered tape is brought into its end position and the rotation of the shaft 102 is stopped, the charge and discharge control for the condenser C, and C, are fully charged, flow of current I, will also cease.

Thus, the base current of transistor TR, becomes considerably smaller than before and a predetermined voltage as V, will be generated. By the presence of the voltage V,, a base current I; (about lO-lS ma.) will flow at the transistor TR, and plunger coil 105 will be supplied with an energizing current I, iii BI, (B being the current amplifying factor of transistor TR,) and the coil 105 being energized to open the relay switch 106. Current from the power source is thus interrupted and the pop-up operation is brought about by means of a certain mechanism, not shown, adapted for being controlled by the plunger actuated by the coil 105.

The embodiments of the invention in which an exclusive property or privilege is claimed are as follows:

1.-In a switch assembly having rotatable slipring means and relatively stationary brush means, said slipring means comprises rotatable directly in said sleeve means, ring means mounted on said sleeve means for rotation therewith and including insulating segments and conductive segments arranged alternately about the circumference of said sleeve means with said conductive segments disposed in contact with said sleeve means, and at least one additional annular groove means formed in the periphery of said alternately arranged conductive and insulating segments.

2. In a switch assembly as set forth in claim 1, said stationary brush means comprising a plurality of resilient electrically conductive contact wires and insulating means for mounting said wires in resilient engagement with each of said groove means respectively.

3. In a switch assembly as set forth in claim 1, wherein said ring means is comprised of an insulating ring and the conductive ring disposed contiguously to each other, said insulating ring having a plurality of axially directed segments and said conductive ring having a plurality of axially directed segments and said conductive ring a plurality of radially extending segments disposed alternately between said axially extending insulated segments.

4. In a switch assembly as set forth in claim 3 further comprising an additional contact ring disposed contiguously to the opposite side of said insulating ring, said insulating ring having a plurality of oppositely extending axially directed insulating segments, and second additional groove means circumferentially formed in the additional conductive and insulating segments.

5. In a switch assembly as set forth in claim 4 wherein the alternating conductive and insulating segments on one side of the insulating ring are out of phase with the alternating conductive and insulating segments on the opposite side of said insulating ring.

6. In a switch assembly as set forth in claim 5 wherein said stationary contact means is comprised of a plurality of resilient electrically conductive contact wires and insulating means for mounting said contact wires in resilient engagement with each of said groove means respectively. 

1. In a switch assembly having rotatable slipring means and relatively stationary brush means, said slipring means comprises rotatable electrically conductive sleeve means, first annular groove means formed directly in said sleeve means, ring means mounted on said sleeve means for rotation therewith and including insulating segments and conductive segments arranged alternately about the circumference of said sleeve means with said conductive segments disposed in contact with said sleeve means, and at least one additional annular groove means formed in the periphery of said alternately arranged conductive and insulating segments.
 2. In a switch assembly as set forth in claim 1, said stationary brush means comprising a plurality of resilient electrically conductive contact wires and insulating means for mounting said wires in resilient engagement with each of said groove means respectively.
 3. In a switch assembly as set forth in claim 1, wherein said ring means is comprised of an insulating ring and the conductive ring disposed conTiguously to each other, said insulating ring having a plurality of axially directed segments and said conductive ring having a plurality of radially extending segments disposed alternately between said axially extending insulated segments.
 4. In a switch assembly as set forth in claim 3 further comprising an additional contact ring disposed contiguously to the opposite side of said insulating ring, said insulating ring having a plurality of oppositely extending axially directed segments and said additional conductive ring having a plurality of radially directed segments disposed alternately with respect to the additional axially directed insulating segments, and second additional groove means circumferentially formed in the additional conductive and insulating segments.
 5. In a switch assembly as set forth in claim 4 wherein the alternating conductive and insulating segments on one side of the insulating ring are out of phase with the alternating conductive and insulating segments on the opposite side of said insulating ring.
 6. In a switch assembly as set forth in claim 5 wherein said stationary contact means is comprised of a plurality of resilient electrically conductive contact wires and insulating means for mounting said contact wires in resilient engagement with each of said groove means respectively. 